A cyclic process of peptide design, peptide synthesis and peptide conformation study will be used to refine methods of determining oligopeptide conformation in solution and predicting it from amino acid sequence. The principal technique for conformation study will be high resolution nuclear magnetic resonance, coupled with model building and empirical calculation of conformation. Correlations will be made with optical (ORD, CD) data and crystallographic results. The peptides to be used in this work will be (a) synthetic cyclic oligopeptides, chiefly those containing one or more basic amino acid side chains, which will also be screened for antibiotic activity; and (b) linear oligopeptides, which it is desired to design so that the chain folds into strongly preferred conformations othr than helical.